Long-wave infrared integrated refrigeration optical system

Abstract

The invention discloses a long-wave infrared integrated refrigeration optical system, which comprises a window, a cold diaphragm, an integrated refrigeration lens group, a band-pass optical filter and a refrigeration sensor which are sequentially arranged from an object space to an image space, the integrated refrigeration lens group comprises N refrigeration lenses, and N is greater than or equal to 3; 8-12 [mu] m infrared light can penetrate through the band-pass optical filter, and light outside the band range can be filtered out; the cold diaphragm, the integrated refrigeration lens group, the band-pass optical filter and the refrigeration sensor are packaged in the Dewar flask; the window sheet is in butt joint with the Dewar flask through a mechanical device to form a long-wave infrared integrated refrigeration optical system. The position limitation of the cold diaphragm in the lens group is broken, so that the cold diaphragm does not need to be strictly positioned behind the lens group, and a greater design freedom degree is provided for an optical system; and meanwhile, the integrated refrigeration lens group is packaged in the Dewar flask, so that the number of optical elements which have temperature difference with the refrigeration sensor is effectively reduced, the temperature stability of the system can be improved, and the negative influence caused by the cold reflection effect is effectively reduced.

Description

Technical Field

[0001] The invention relates to the field of refrigerated long-wave infrared optical systems, and in particular to a long-wave infrared integrated refrigerated optical system. Background Art

[0002] The cooled long-wave infrared optical imaging system can collect the spontaneous radiation light of objects for thermal imaging. It also has the characteristics of strong anti-interference ability, high temperature sensitivity, and high signal-to-noise ratio. It is widely used in temperature measurement, night monitoring, fire detection, target tracking and other fields.

[0003] Due to the extremely high sensitivity of the cooled long-wave infrared optical imaging system, spontaneous radiation generated by the inner wall of the lens barrel, non-target heat sources, etc., if reaching the detector, may cause serious interference to the imaging results of the optical system. In order to suppress stray light interference and improve system stability, the cooled long-wave infrared optical imaging system usually requires a cold aperture efficiency of 100%. In order to achieve 100% cold aperture efficiency, the cold aperture is usually required as the aperture aperture of the entire optical system during design, and is located behind the optical system lens group. This imposes constraints on the design and optimization process of the lens group, which is not conducive to finding the optimal solution for the optical design.

[0004] At the same time, when there is a large temperature difference between the optical system and the cooled infrared detector, the cold reflection phenomenon will cause black spots to appear in the image received by the detector, which will further reduce the image quality of the cooled long-wave infrared optical imaging system. In order to reduce the interference caused by the cold reflection phenomenon, it is usually necessary to constrain the cold reflection characteristic indicators in the optical system or correct the image, which increases the complexity of system design and image processing. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a long-wave infrared integrated refrigeration optical system, which breaks the position restriction of the cold aperture in the optical system by encapsulating some lenses and sensors in the optical system lens group into a Dewar flask, thereby providing a higher degree of freedom in optical design, improving the temperature stability of the optical system and reducing the adverse effects of cold reflection effect on the imaging of the optical system.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A long-wave infrared integrated refrigeration optical system, comprising a window, a cold aperture, an integrated refrigeration lens group, a bandpass filter and a refrigeration sensor arranged in sequence from the object side to the image side, wherein the integrated refrigeration lens group comprises N refrigeration lenses, where N is greater than or equal to 3;

[0008] The bandpass filter is a bandpass filter that can transmit 8-12 μm infrared light and filter out light outside this band;

[0009] The cold aperture, the integrated refrigeration lens group, the bandpass filter and the refrigeration sensor are packaged in a Dewar flask; the window is docked with the Dewar flask through a mechanical device to form the long-wave infrared integrated refrigeration optical system.

[0010] In order to achieve thermal performance compensation of the Dewar device, the window and its mechanical structure, the material of the window is chalcogenide glass, the material of the first N-1 cooling lenses of the integrated cooling lens group is chalcogenide glass, and the material of the Nth cooling lens is zinc sulfide.

[0011] In order to achieve lightweight of the lens group and meet the requirements of the side bonding assembly method, the shape of the window piece and the N cooling lenses of the integrated cooling lens group are all meniscus lenses.

[0012] In order to capture the thermal radiation information of distant targets, the focal length f of the long-wave infrared integrated refrigeration optical system in a working state satisfies 70mm≤f≤80mm, and the half field of view FOV satisfies 4.5°≤FOV≤5°.

[0013] In order to collect more infrared light energy and realize large relative aperture imaging, the aperture number F of the long-wave infrared integrated refrigeration optical system in the working state satisfies the following relationship: 2.25≤F≤2.75.

[0014] In order to achieve high compactness of the long-wave infrared integrated refrigeration optical system, the total system length TTL of the long-wave infrared integrated refrigeration optical system in a working state satisfies the following relationship: 52.5 mm≤TTL≤57.5 mm.

[0015] In order to realize the miniaturization and lightness of the Dewar flask device, the aperture D of the window is W and the diameter D of the cold diaphragm S Satisfies the following relationship: D W / D S ≥2.5.

[0016] In order to improve the window's ability to regulate infrared light and compensate for the system's chromatic aberration, the front surface of the window is a spherical surface, and the back surface is a binary diffraction surface with an even-order aspherical surface as the base. The aspherical base profile satisfies the following expression:

[0017] ;

[0018] Where c is the curvature of the surface vertex, k is the cone coefficient, r is the radial distance, and α 2i is the even aspheric coefficient;

[0019] The diffraction additional phase satisfies the following expression:

[0020] ;

[0021] Among them, r is the radial distance, R is the normalized radius, β 2i is the even-order diffraction coefficient.

[0022] In order to improve the correction capability of the integrated refrigeration lens group for system aberrations, the front surfaces of the N refrigeration lenses of the integrated refrigeration lens group are all spherical surfaces, and the rear surfaces are all even-order aspherical surfaces. The surface profile of the even-order aspherical surface satisfies the following expression:

[0023] ;

[0024] Where c is the curvature of the surface vertex, k is the cone coefficient, r is the radial distance, and α 2i is the even aspheric coefficient.

[0025] In order to realize the telephoto system structure and reduce the aperture size of the Dewar flask, the optical focal length of the window is greater than 0, and the optical focal length of the integrated refrigeration lens group is less than 0.

[0026] Through the above technical solution provided by the present invention, the following beneficial effects can be achieved:

[0027] (1) The position restriction of the cold stop in the lens group is broken, so that it does not need to be strictly located behind the lens group, but can be located between the window and the integrated cooling lens group. Compared with other cooling long-wave infrared optical systems, the technical solution provided by the present invention can provide greater freedom in optical design.

[0028] (2) By packaging the integrated refrigeration lens group into a Dewar flask, its operating temperature is kept constant at the ultra-low temperature environment temperature inside the Dewar flask, thereby reducing the number of components and devices in the optical system that have a temperature difference with the refrigeration sensor, thereby reducing the adverse effects of the cold reflection effect on the refrigeration type long-wave infrared optical imaging system and improving the temperature stability of the system.

[0029] (3) Due to the improvement of the freedom of optical design, the present invention can realize a large relative aperture and compact design of a cooled long-wave infrared optical system, so that the system can achieve high-resolution, high-definition, near-diffraction-limited imaging within a large range of ambient temperature changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 4 is a system structure diagram of a long-wave infrared integrated refrigeration optical system in an embodiment of the present invention.

[0031] Figure 2 It is a phase distribution diagram of the diffraction surface in the long-wave infrared integrated refrigeration optical system in an embodiment of the present invention.

[0032] Figure 3 This is a ray tracing diagram of the long-wave infrared integrated refrigeration optical system in a fixed-focus state in an embodiment of the present invention.

[0033] Figure 4 It is a point diagram of the long-wave infrared integrated refrigeration optical system in the embodiment of the present invention under normal temperature working state.

[0034] Figure 5 It is an MTF curve diagram of the long-wave infrared integrated refrigeration optical system in the embodiment of the present invention under normal temperature working state.

[0035] Figure 6 This is a field curvature distortion diagram of the long-wave infrared integrated refrigeration optical system in the embodiment of the present invention under normal temperature working state.

[0036] Figure 7 It is a point diagram of the long-wave infrared integrated refrigeration optical system in the embodiment of the present invention under low-temperature working state.

[0037] Figure 8 This is an MTF curve diagram of the long-wave infrared integrated refrigeration optical system in the embodiment of the present invention under low-temperature working conditions.

[0038] Fig. 9 This is a field curvature distortion diagram of the long-wave infrared integrated refrigeration optical system in the embodiment of the present invention under low-temperature working conditions.

[0039] Fig.10 It is a point diagram of the long-wave infrared integrated refrigeration optical system in the embodiment of the present invention under high temperature working state.

[0040] Fig.11 This is an MTF curve diagram of the long-wave infrared integrated refrigeration optical system in an embodiment of the present invention under high temperature working state.

[0041] Fig.12 This is a field curvature distortion diagram of the long-wave infrared integrated refrigeration optical system in an embodiment of the present invention under high-temperature working conditions.

[0042] Fig.13 It is the system structure diagram of the cooling long-wave infrared optical system in the comparative example.

[0043] Fig.14 This is the ray tracing diagram of the cooling long-wave infrared optical system in the comparative example under fixed focus.

[0044] Fig.15 It is a point diagram of the refrigerated long-wave infrared optical system in the comparative example under normal temperature working condition.

[0045] Fig.16 It is the MTF curve of the cooling long-wave infrared optical system in the comparative example under normal temperature working state.

[0046] Fig.17 It is a point diagram of the refrigerated long-wave infrared optical system in the comparative example under low-temperature working conditions.

[0047] Fig.18 It is the MTF curve of the refrigerated long-wave infrared optical system in the comparative example under low-temperature working condition.

[0048] Fig.19 It is a point diagram of the refrigerated long-wave infrared optical system in the comparative example under high temperature working condition.

[0049] Fig. 20 It is the MTF curve of the cooling long-wave infrared optical system in the comparative example under high temperature working state. DETAILED DESCRIPTION

[0050] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments, and the purpose and effects of the present invention will become more clear. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0051] like Figure 1 As shown, the long-wave infrared integrated refrigeration optical system proposed in the present invention includes a window W, a cold aperture S, an integrated refrigeration lens group LG, a bandpass filter BP and a refrigeration sensor D arranged in sequence from the object side to the image side, wherein the integrated refrigeration lens group LG includes N refrigeration lenses arranged in sequence from the object side to the image side. In this embodiment, N=3, which are refrigeration lens 1 L1, refrigeration lens 2 L2 and refrigeration lens 3 L3 respectively.

[0052] Among them, the window W is used to collect the infrared light spontaneously radiated by the target, the cold aperture S is used to suppress stray light, the integrated refrigeration lens group LG is used to change the position of the cold aperture S in the lens group and perform aberration correction, the bandpass filter BP is used to filter out the stray light outside the 8-12μm band range, and the refrigeration sensor D is used to sense the infrared light collected by the system and convert it into an infrared image.

[0053] In this embodiment, the material of the bandpass filter BP is germanium, and the thickness is 0.3 mm. The resolution of the cooling sensor D is 640×512, and the pixel size is 15 μm.

[0054] In order to collect the infrared light spontaneously radiated by the target and compress the aperture of the Dewar flask, the focal length of the window W is Should meet: In order to transmit the infrared light passing through the cold aperture S to the cooling sensor D and fill the entire photosensitive surface, the focal length of the cooling integrated lens group LG Should meet: .

[0055] In this embodiment, the cooling lens 1 L1 and the cooling lens 2 L2 in the integrated cooling lens group LG have a larger negative focal length, which is mainly used to transmit and diverge infrared light, and the cooling lens 3 L3 has a smaller positive focal length, which is mainly used for aberration correction.

[0056] In this embodiment, the materials of the window W, cooling lens 1 L1, cooling lens 2 L2 and cooling lens 3 L3 are chalcogenide glass, chalcogenide glass, chalcogenide glass and zinc sulfide respectively, and the shapes of all of them are meniscus lenses.

[0057] In this embodiment, the front surfaces of the cooling lens 1 L1, the cooling lens 2 L2, and the cooling lens 3 L3 are all spherical surfaces, and the rear surfaces are all even-order aspherical surfaces. The surface profile of the even-order aspherical surface satisfies the following expression:

[0058]

[0059] Where c is the curvature of the surface vertex, k is the cone coefficient, r is the radial distance, and α 2i is the even aspheric coefficient.

[0060] In this embodiment, the front surface of the window W is a spherical surface, and the rear surface is a binary diffraction surface with an even-order aspherical surface as the base. The profile of the aspherical base satisfies the above expression of z(r), and the diffraction additional phase satisfies the following expression:

[0061]

[0062] Among them, r is the radial distance, R is the normalized radius, β 2i is the even-order diffraction coefficient.

[0063] The assembly method of the entire optical system is as follows: at room temperature, the cold aperture S, the integrated refrigeration lens group LG, the bandpass filter BP and the refrigeration sensor D are encapsulated into the Dewar flask, and the window W is connected to the Dewar flask through a mechanical device to form a long-wave infrared integrated refrigeration optical system.

[0064] The focusing state of the entire optical system is as follows: after the room temperature assembly process of the optical system is completed, the Dewar flask is cooled to -123°C and kept constant, the working environment of the window W and its mechanical device is +10°C, and the thickness between the window W and the cold aperture S is used for focusing compensation.

[0065] The working state of the entire optical system is as follows: the Dewar flask is cooled to -123°C and kept constant as its stable working environment state; the working environment of the window W and its mechanical device varies in the temperature range of -40°C to +60°C.

[0066] In this embodiment, the system parameters are optimized by ray tracing method. Table 1 below gives the system structure parameters of this embodiment under normal temperature assembly state. Table 2 and Table 3 respectively give the even-order aspheric surface parameters and diffraction surface parameters of this embodiment under normal temperature assembly state.

[0067] Table 1 System structure parameters of this embodiment under normal temperature assembly state

[0068]

[0069] Table 2 Even-order aspheric parameters of this embodiment in room temperature assembly state

[0070]

[0071] Table 3 Diffraction surface parameters of this embodiment under room temperature assembly state

[0072]

[0073] The phase distribution diagram of the diffraction surface under the parameters in Table 3 is as follows: Figure 2 shown.

[0074] Under the parameters in Table 1, Table 2, and Table 3, the ray tracing diagram of the system in the fixed focus state is as follows: Figure 3 As shown in the figure, the system has good light focusing and reasonable lens structure distribution.

[0075] In order to more clearly illustrate the working state of the system within a certain temperature range, the working state of the system is divided into normal temperature working state (the working temperature of the window W is +10℃, the working temperature of the Dewar flask is -123℃), low temperature working state (the working temperature of the window W is -40℃, the working temperature of the Dewar flask is -123℃) and high temperature working state (the working temperature of the window W is +60℃, the working temperature of the Dewar flask is -123℃).

[0076] Under normal temperature working condition, the system's point diagram, MTF curve, and field curvature distortion diagram are as follows: Figure 4 , Figure 5 , Figure 6 As shown; Under low temperature working conditions, the system's point diagram, MTF curve, and field curvature distortion diagram are shown as follows: Figure 7 , Figure 8 , Fig. 9 As shown; Under high temperature working conditions, the system's point diagram, MTF curve, and field curvature distortion diagram are shown as follows: Fig.10 , Fig.11 , Fig.12 shown.

[0077] The RMS radius of the spot diagram reflects the energy concentration and imaging quality of optical imaging, and the Airy disk represents the minimum spot diagram spot size that the optical system can achieve. Under normal temperature working conditions, low temperature working conditions, and high temperature working conditions, the maximum RMS radius of the system under five fields of view is 16.315μm, 16.399μm, and 16.579μm, respectively. The spot diagram spot size is similar to the Airy disk size and matches the pixel size of the cooled detector D of 15μm.

[0078] The MTF curve can comprehensively reflect the imaging quality of the optical system, and the diffraction limit reflects the highest imaging quality that the optical system can achieve. Under normal temperature working conditions, low temperature working conditions, and high temperature working conditions, the MTF value of the system at a spatial frequency of 17lp / mm is higher than 0.4, which is close to the diffraction limit.

[0079] The results of the spot diagram and MTF curve well illustrate that the embodiment of the present invention can increase the degree of freedom of optical design, enabling the refrigerated long-wave infrared optical system to achieve near-diffraction-limited imaging. Under different ambient temperatures, the spot diagram and MTF curve of this embodiment fluctuate very little, proving that the scheme of the present invention is conducive to improving the temperature stability of the optical system.

[0080] Distortion reflects the deviation between the actual image shape and the ideal image shape. Under normal temperature working state, low temperature working state, and high temperature working state, the maximum distortion of the system is 1.4663%, 1.4654%, and 1.4673%, respectively. Under different working conditions, the maximum distortion of the system does not exceed 1.5%, which proves the superior performance of the embodiment of the present invention.

[0081] In different temperature environments, the focal length of the embodiment of the present invention is close to 75mm, the image side F number is 2.5, the total length of the system is close to 55mm, and the half field angle is close to 4.78°. The following Table 4 gives the specific key performance parameters of the embodiment of the present invention in three working states.

[0082] Table 4 Key performance parameters of this embodiment under three working conditions

[0083]

[0084] The long-wave infrared integrated refrigeration optical system of this embodiment has the characteristics of small field of view, long focal length, large relative aperture, compact structure, and high temperature stability. It can achieve near-diffraction limit imaging and can be applied to major fields such as night reconnaissance and target recognition.

[0085] Comparative Example

[0086] A refrigerated long-wave infrared optical system, whose design index, lens material and surface shape, and system length are the same as those of the embodiment of the present invention, and the optical structure is as follows Fig.13As shown, it is composed of a lens group OLG, a cold diaphragm OS, a bandpass filter OBP and a cooling sensor OD arranged in sequence from the object side to the image side. The difference from the embodiment of the present invention is that the system structure of the comparative example is consistent with the mainstream traditional cooling type long-wave infrared optical system, that is, the cold diaphragm OS of the system is located behind the lens group OLG, the working environment temperature of the lens group OLG and its mechanical structure is -40℃~60℃, the cold diaphragm OS, the filter OBP and the cooling sensor OD are packaged in a Dewar flask, and the working environment temperature is -123℃.

[0087] The focus state of the comparative example is similar to that of the embodiment of the present invention, that is, when the working temperature of the lens group OLG is +10°C and the working temperature of the Dewar flask is -123°C, the thickness between the lens group OLG and the cold stop OS is used for focus compensation. In this state, the ray tracing diagram of the comparative example is as follows: Fig.14 Under the condition of the same system length as the embodiment of the present invention, the light refracted in the comparative example is more severe, and is more sensitive to tolerances. The excessive curvature of the meniscus lens in the system requires higher processing and assembly accuracy. At the same time, due to the position limitation of the cold light stop OS, the overall size of the lens group OLG is close to twice the size of the window W in this embodiment.

[0088] The working conditions of the comparative example are also divided into three types, namely, normal temperature working condition (OLG working temperature is +10℃, Dewar flask working temperature is -123℃), low temperature working condition (OLG working temperature is -40℃, Dewar flask working temperature is -123℃) and high temperature working condition (OLG working temperature is +60℃, Dewar flask working temperature is -123℃). Under normal temperature working condition, the point diagram and MTF curve diagram of the comparative example are as follows: Fig.15 , Fig.16 As shown; Under low temperature working conditions, the point diagram and MTF curve diagram of the comparative example are as follows Fig.17 , Fig.18 As shown; Under high temperature working conditions, the point diagram and MTF curve diagram of the comparative example are as follows Fig.19 , Fig. 20 shown.

[0089] In the normal temperature working state, low temperature working state, and high temperature working state, the maximum RMS radius of the comparative example under five fields of view is 37.773μm, 36.069μm, and 40.488μm respectively. The RMS radius of the spot diagram far exceeds the spot diagram spot size in the embodiment of the present invention, and the spot diagram spot has a significant increasing trend as the field of view increases, which easily causes the problem that the center of the captured image is clear but the surroundings are blurred.

[0090] Under normal temperature working state, low temperature working state and high temperature working state, the MTF curves of the comparison ratio under five fields of view show that the image quality of small field of view is good while the image quality of large field of view is poor and is greatly affected by temperature. The MTF value of the maximum field of view at a spatial frequency of 17lp / mm is only close to 0.1, which can no longer meet the use requirements.

[0091] According to the results of the embodiments of the present invention and the comparative examples, a comparison is made between the long-wave infrared integrated refrigeration optical system and the traditional refrigeration type long-wave infrared optical system, as shown in Table 5.

[0092] Table 5 Performance comparison between the long-wave infrared integrated cooling optical system and the traditional cooling long-wave infrared optical system

[0093]

[0094] In summary, compared with other refrigerated long-wave infrared optical systems, the long-wave infrared integrated refrigeration optical system proposed in the present invention breaks the limitation of the cold aperture position, improves the freedom of optical design and effectively reduces the size of the lens, reduces the influence of cold reflection phenomenon on the imaging results, can achieve near-diffraction limit imaging, and has the characteristics of compactness, large relative aperture, low distortion and high temperature stability.

[0095] In the present invention, the terms "first", "second", "third", etc. are used to distinguish similar objects and should not be understood as indicating or implying relative importance.

[0096] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. A long-wave infrared integrated refrigeration optical system, characterized in that: It includes a window, a cold stop, an integrated refrigeration lens group, a bandpass filter and a refrigeration sensor arranged in sequence from the object side to the image side, wherein the integrated refrigeration lens group includes N refrigeration lenses, where N is greater than or equal to 3; The bandpass filter is a bandpass filter that can transmit 8-12 μm infrared light and filter out light outside this band; The cold aperture, the integrated refrigeration lens group, the bandpass filter and the refrigeration sensor are packaged in a Dewar flask; the window is docked with the Dewar flask through a mechanical device to form the long-wave infrared integrated refrigeration optical system.

2. The long-wave infrared integrated refrigeration optical system according to claim 1, characterized in that: The material of the window piece is chalcogenide glass, the material of the first N-1 cooling lenses of the integrated cooling lens group is chalcogenide glass, and the material of the Nth cooling lens is zinc sulfide.

3. The long-wave infrared integrated refrigeration optical system according to claim 1, characterized in that: The window piece and the N cooling lenses of the integrated cooling lens group are all in the shape of meniscus lenses.

4. The long-wave infrared integrated refrigeration optical system according to claim 3, characterized in that: The focal length f of the long-wave infrared integrated refrigeration optical system in a working state satisfies 70 mm≤f≤80 mm, and the half field of view FOV satisfies 4.5°≤FOV≤5°.

5. The long-wave infrared integrated refrigeration optical system according to claim 4, characterized in that: The aperture number F of the long-wave infrared integrated refrigeration optical system in a working state satisfies the following relationship: 2.25≤F≤2.

75.

6. The long-wave infrared integrated refrigeration optical system according to claim 5, characterized in that: The total system length TTL of the long-wave infrared integrated refrigeration optical system in a working state satisfies the following relationship: 52.5 mm≤TTL≤57.5 mm.

7. The long-wave infrared integrated refrigeration optical system according to claim 1, characterized in that: The aperture D of the window W and the cold stop D S The caliber satisfies the following relationship: D W / D S ≥2.

5.

8. The long-wave infrared integrated refrigeration optical system according to claim 1, characterized in that: The front surface of the window is a spherical surface, and the rear surface is a binary diffraction surface with an even-order aspherical surface as the base. The profile of the aspherical base satisfies the following expression: ； Where c is the curvature of the surface vertex, k is the cone coefficient, r is the radial distance, and α 2i is the even aspheric coefficient; The diffraction additional phase satisfies the following expression: ； Among them, r is the radial distance, R is the normalized radius, β 2i is the even-order diffraction coefficient.

9. The long-wave infrared integrated refrigeration optical system according to claim 1, characterized in that: The front surfaces of the N cooling lenses of the integrated cooling lens group are all spherical surfaces, and the rear surfaces are all even-order aspherical surfaces. The surface profile of the even-order aspherical surface satisfies the following expression: ； Where c is the curvature of the surface vertex, k is the cone coefficient, r is the radial distance, and α 2i is the even aspheric coefficient.

10. The long-wave infrared integrated refrigeration optical system according to claim 8, characterized in that: The optical focal length of the window is greater than 0, and the optical focal length of the integrated refrigeration lens group is less than 0.

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